AUTHOR=Guo Mengjiao , Zhang Congyue , Zhang Chengcheng , Zhang Xiaorong , Wu Yantao 

TITLE=Lacticaseibacillus rhamnosus Reduces the Pathogenicity of Escherichia coli in Chickens

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.664604

DOI=10.3389/fmicb.2021.664604

ISSN=1664-302X

ABSTRACT=<p><italic>Lacticaseibacillus rhamnosus</italic> is a recognized probiotic that is widely used in scientific research and clinical applications. This study found that the <italic>Lacticaseibacillus rhamnosus</italic> GG (LGG) strain can reduce the adhesion of <italic>Escherichia coli</italic> (<italic>E. coli</italic>) to primary chicken intestinal epithelial cells by 75.7% and inhibit 41.7% of the <italic>E. coli</italic> that adhere to intestinal epithelial cells. Additionally, LGG showed strong inhibitory ability on the growth of <italic>E. coli</italic>, <italic>Staphylococcus aureus</italic>, <italic>Salmonella</italic> Paratyphi B, and <italic>Salmonella</italic> Enteritidis <italic>in vitro</italic>. Furthermore, the influence of LGG on the growth performance, intestinal flora, immunity, and disease resistance of chickens was explored. Chickens fed with LGG exhibited increased average daily weight gain and concentrations of sIgA, IgG, and IgM than did controls. After 21 days of feeding, a diet with LGG increased the diversity of intestinal microbiota and maintained intestinal health. Moreover, LGG promoted immunologic barriers by upregulating cytokines and chemokines via the Toll-like receptor. The major pro-inflammatory factors, including <italic>Myd88</italic>, <italic>NF-</italic>κ<italic>B</italic>, <italic>Il6</italic>, and <italic>Il8</italic>, were upregulated compared to controls. After being challenged with <italic>E. coli</italic>, the survival rate of chickens fed with LGG was significantly higher than those in the control group, and decreased numbers of <italic>E. coli</italic> were detected in the heart and lungs of the LGG group. In summary, oral administration of LGG to chickens could improve growth performance, maintain intestinal homeostasis, and enhance innate immune response and disease resistance.</p>